A Downtown Denver Law Firm Leverages Tenant Improvement Funds To Reduce Energy Consumption

Transcription

1 Building Technologies OFFIC A Downtown Denver Law Firm Leverages Tenant Improvement Funds To Reduce nergy Consumption Bryan Cave LLP (formerly Holme Roberts & Owen LLP, headquartered in Denver, Colorado), is an international law firm. It partered with the U.S Department of nergy (DO) to develop and implement solutions to retrofit existing buildings to reduce annual energy consumption by at least 30% versus pre-retrofit energy use as part of DO s Commercial Building Partnership (CBP) program. 1 The National Renewable nergy Laboratory (NRL) provided technical expertise. PG Office Trust (the landlord), Fitzmartin Consulting, and Xcel nergy also collaborated on the project. Bryan Cave LLP leases more than 100,000 ft 2 of office space on five floors in the 52-story Wells Fargo Center, an iconic downtown landmark designed by Philip Johnson and John Burgee, built in nergy improvements were made to all of the company s floors as part of the lease renewal/officeupdating program; this case study presents results for the 42nd floor, which include reception, conferencing, and office areas. By making energy-smart choices in its owner-funded tenant improvement (TI) work, Bryan Cave LLP was able to achieve the desired look and feel for its offices and significantly reduce energy use, all with no direct out-of-pocket expenditures. Utility bills were not available for the project (utilities in the all-electric building are charged per square foot). xpected and measured cost reductions by end use are shown in the graph below. easurements from an onsite submetering system showed annual savings of 19% versus pre-retrofit use from ay 2012 through April 2013, falling below the project goal because plug loads were higher than expected and fan energy savings lower than expected. xcluding plug loads, savings were 31% versus pre-retrofit. Savings was also benchmarked against the requirements of ASHRA/ANSI/ISNA nergy Standard xpected and easured nergy Cost Reductions lectricity Savings Heating Cooling Interior Lighting quipment Fans -$1,000 -$45 $1,300 $1,950 -$1,650 $350 $2,000 $3,500 $6,500 $6,000 The Bryan Cave LLP office incorporates energy efficiency in a modern design. Photo by Dennis Schroeder, NRL Project Type Climate Zone Owner or Tenant Barrier Addressed Office building, retrofit ASHRA Zone 5B, cool and dry Tenant Square Footage 24,510 ft 2 easured nergy Savings (Versus Pre-Retrofit) Cost Reductions (Versus Pre- Retrofit) 3 Simple Payback Period xpected Carbon Dioxide missions Avoided 4 Tenant/owner split incentive 19% 74,000 kilowatt-hours (kwh)/yr of electricity $7,000/yr 3.5 yrs 50 metric tons/yr Construction Completion October CBP is a public/private, cost-shared initiative that demonstrates cost-effective, replicable ways to achieve dramatic energy savings in commercial buildings. Through the program, companies and organizations, selected through a competitive process, team with DO and national laboratory staff who provide technical expertise to explore energy-saving ideas and strategies that are applied to specific building project(s) and that can be replicated across the market. 2 ASHRA 90.1: document-history# Using $0.09/kWh provided by Bryan Cave LLP 4 PA Greenhouse Gas quivalencies Calculator: : XPCTD : ASURD Dollars Per Year Savings

2 2 Building Technologies OFFIC Decision Criteria The decision by Bryan Cave LLP and the building owner, PG Office Trust, to pursue dramatic energy savings and the choice of strategies by Bryan Cave LLP reflected economic and noneconomic considerations. conomic Bryan Cave LLP did not have hard and fast criteria to screen energy efficiency measures (s). Rather, it had a budget in mind, ranked candidate s by their estimated return on investment, and selected s from the list until the project budget was reached. Bryan Cave LLP did not receive a utility discount from the building owner for reduced consumption. Investments in energy efficiency in office space can pay back quickly with large long-run cost savings. ven without considering tax benefits, the project presented here was expected to pay back within 3 years when utility rebates were accounted for. Several s, such as using lighter tinted window glass to improve access to daylight were considered but not implemented because of architectural limitations such as the need to preserve the uniformity of the building exterior; their impact was not modeled. Cost of conserved energy (CC, the cost of an efficiency upgrade divided by its discounted kilowatt-hour or therm savings 6 ), is included in the business case information. CC can be compared to the utility rate for electricity to assess whether it is cheaper over the long term to buy energy or to save that energy by retrofitting. The CC of some measures exceeds the utility rate, but the whole project cost is only $0.07/kWh saved over 5 years. Net present value and C in the table were calculated using a 5-year analysis period and 3% nominal discount rate. Branding The decision-making process was also driven by considerations such as Bryan Cave LLP s desire to attract top clients and talent by openly demonstrating its commitment to sustainability. Operational Bryan Cave LLP s client confidentiality is extremely important, so attorneys office walls are built from deck to deck. Such walls are expensive to move and may preclude certain s. Although using exterior window glass with a lighter tint could improve the opportunity to use daylighting, it was not an option because the uniformity of the building exterior had to be preserved. Policy National policy issues that impact energy efficiency choices include tax policy that incentivizes efficiency investments such as the PAct 179D federal energy tax deduction 5 and model building energy codes and standards, which provide a starting point for thinking about energy efficiency. nergy fficiency easures Bryan Cave LLP decided to implement the s shown in the table on page 3. The s should be applicable in all climate types. The nighttime lighting loads were reduced as a result of the vacancy sensors, which are similar to occupancy sensors except that they are manual on/automatic off. The plug loads will be reduced as the company replaces computing equipment over time with more energy-efficient items as part of its normal equipment replacement activity. The total cost of the s was equivalent to $1.62/ft 2 after accounting for utility rebates. Vacancy sensors turn the lights off when a room is unoccupied, helping to reduce daytime and nighttime energy use. These sensors differ from occupancy sensors in that vacancy sensors must be switched on manually, eliminating the problem of lights being switched on unnecessarily, for example where there is sufficient daylight to perform a certain task. Bryan Cave LLP chose to install vacancy sensors on all floors of its Denver headquarters. Photo by Dennis Schroeder, NRL DO 179D Calculator: 6 eier, A.K The Cost of Conserved nergy as an Investment Statistic. SL- I , Lawrence Berkeley Laboratory. Available at bitstream/handle/1969.1/94751/sl-i pdf?sequence=1

3 nergy fficiency easure Implemented in This Project Owner Will Consider for Future Projects HVAC: 12% Whole-Project nergy Savings xpected Versus Pre-Retrofit Add variable frequency drives to air handling unit fans. Upgrade thermostats and add 3 o F to dead band. Lighting: 22% Whole-Project nergy Savings xpected Versus Pre-Retrofit Balance corridor lighting by reducing lighting power density. xpected Annual Savings xpected Improvement Cost Net Present Value Cost of Conserved nergy Simple Payback kwh/yr $/yr $ $ $/kwh yr Yes Yes 34,000 $3,200 $19,800 $136,200 $ Yes Yes 11,000 $1,000 $4,700 $44,200 $ Yes Yes 18,000 $1,700 $4,500 $79,900 $ Upgrade downlight lamps. Yes Yes 25,000 $2,400 $3,300 $111,600 $ Install vacancy sensors. Yes Yes 24,000 $2,300 $10,000 $100,100 $ Reduce night light and plug loads. Yes Yes 17,000 $1,600 $0 $76,300 $ Subtotals 129,000 $12,200 $42,300 $548,300 $ Building Technologies OFFIC 3

4 4 Building Technologies OFFIC nergy Use Intensities by nd Use nergy modeling was an integral part of the design process for the Bryan Cave LLP retrofit project, enabling the design team to assess whether the s selected for the retrofit could achieve the project s energy savings target. odeled energy cost reductions were also used by Bryan Cave LLP to screen s based on their economic returns. To calculate whole-building energy savings, three energy models were created, as described below. The graph at the bottom of this page shows a comparison of the end use energy consumption breakdown of the three models and measured energy use using annual energy consumption divided by floor area, also known as energy use intensity (UI). Tables of energy consumption and energy savings by end use are shown on page 5. Code Baseline The first energy model represented minimal compliance with the requirements of ASHRA for the building envelope properties, installed lighting power, and heating, ventilating, and air-conditioning (HVAC) equipment efficiency, and ASHRA for ventilation for Denver, Colorado. The code baseline model had an UI of 48 kbtu/ft 2. Pre-Retrofit The second model represented the Bryan Cave LLP space as it existed before the retrofit work. The space was served by a constant volume dual-deck distribution system with electric reheat coils in individual zone ducts. Cooling was handled by electric water chillers in a central plant. The pre-retrofit model used 53 kbtu/ft 2, which was higher than the code baseline because the building construction predated ASHRA Final Design The final model incorporated the s used in the retrofit project. This model had an annual UI of 33 kbtu/ft 2, corresponding to a savings of 38% versus pre-retrofit energy use, due mainly to the retrofit of variable-speed fan drives to the air handling units and lighting power reduction. easured nergy Use From ay 2012 through April 2013 measured energy use was 43 kbtu/ft 2, 19% below pre-retrofit levels. However much of the discrepancy between measured and expected savings was due to increased plug loads following the retrofit where they were expected to fall slowly over time as equipment was replaced with more efficient options. When considering only loads regulated by energy code, savings were 31% versus pre-retrofit. At the same time, energy savings from the variable speed fan drives fell below expectations. Comparing UI of nergy odels and easured nergy Use 60 Annual UI % SAVINGS 19% SAVINGS Heating (electric) Combined HVAC: Cooling & Pumps (electric) Interior Lighting (electric) quipment (electric) Fans (electric) 0 Code Baseline Pre-retrofit Final Design easured

5 Building Technologies OFFIC 5 Annual nergy Use and Percentage Savings by nd Use Code Baseline Pre- Retrofit Final Design easured nd Use Category Annual UI Annual UI Annual UI Percent Savings versus Pre-Retrofit Annual UI Percent Savings versus Pre-Retrofit Heating (electric) Combined HVAC: Cooling and Pumps (electric) Interior Lighting (electric) quipment (electric) Fans (electric) Total nergy Savings From Implemented s Versus Pre-Retrofit Use by nd Use lectricity nd Use Category xpected Savings (kwh/yr) easured Savings (kwh/yr) Heating -11, Cooling + Pumps 14,000 21,500 Interior Lighting 69,000 67,500 quipment 21,000-18,500 Fans 37,000 4,000 lectricity Total 130,000 74,000 Balancing corridor lighting with workspace lighting is a key aspect of a well-executed lighting design. In the case of Bryan Cave LLP s offices, the corridors were overlit compared to surrounding areas. NRL worked with Bryan Cave LLP s engineering team to develop and implement a lighting plan that provided a pleasing and functional corridor lighting system and also reduced Bryan Cave LLP s energy use by 5%. Photo by Dennis Schroeder, NRL 19321

6 6 Building Technologies OFFIC Lessons Learned Commercial real estate leases often leave landlords and their tenants puzzled about investing in energy savings. Owners who do not pay energy bills have difficulty justifying investments in energy savings. Tenants question why they would want to invest in someone else s building. One implementation model that helped address this barrier for Bryan Cave LLP was to use part of the owner-supplied TI allowance for energy improvements. This strategy provided Bryan Cave LLP an essentially no-cost way to reduce building operating costs and may increase the property value for owners. Applied throughout a property, TIs that reduce energy use may even prolong the life of the facility by reducing the load on the equipment. Other lessons learned are included below, showing best practices for implementing energy efficiency in TI projects to achieve similar results to those presented here. nergy goals motivate change Different energy goals can be used to drive the design process. The CBP goals were chosen because they have been shown to be technically achievable for office space using existing technologies, but still push companies beyond business as usual. Regardless of the goal selected, it provides a focal point to motivate the design team. Incentives can be crafted to promote good design and best practices developed to check that the building performs to expectations following occupancy. Governments sometimes provide energy improvement-based incentives. These vary markedly from area to area and range from tax-based incentives to direct rebates. These incentives can greatly improve the business case for s. Visit the Database of State Incentives for Renewable nergy (DSIR) 8 to identify opportunities in your area. Investing in energy efficiency provided the best mix of meaningful change. It very much aligned with what we were trying to achieve. Randy iller Office anaging Partner at Bryan Cave LLP, Denver Bryan Cave LLP project team from left to right: Greg Stark, NRL; Don Fitzmartin, Fitzmartin Consulting; Nancy Gonzalez, Bryan Cave LLP; Greg Forge, PG Office Trust; Randy iller, Bryan Cave LLP; Randall Glardon, PG Office Trust; ark aguire, formerly of Bryan Cave LLP. Photo by Dennis Schroeder, NRL Understand the current energy use situation Key to an effective project is a clear understanding of a property s energy use and savings potential. For most tenants, this means working with outside organizations, architects, engineers, utilities, and federal, state, and local governments. One place to start, if possible, is by analyzing utility bills. Overall energy use can be compared to the performance of comparable buildings, for example by using the NRGY STAR Portfolio anager. 7 By measuring or estimating consumption by different end uses such as lighting, HVAC, and plug loads, the largest opportunities for savings can be identified. Contact your utility company Utility companies offer incentives ranging from discounted energy audits and cost-shared design assistance programs to rebates for lighting, renewable energy, and custom applications. In some localities, rebates may refund a substantial fraction of the project cost. ven if the local utility s programs are limited, its representatives can help determine where to focus an assessment. In the Bryan Cave LLP retrofit, rebates from the local utility, Xcel nergy, were expected to reduce the cost of the improvements by more than 12%. Carefully commission new equipment During hand-off of the project from the construction team to the tenant, energy-saving equipment must be carefully checked to make sure it is operating properly. For example, during commissioning, a wiring problem was discovered in the vacancy sensors that would have prevented correct operation. Particular attention should be paid to verifying continued proper control and operation of HVAC retrofits such as the variable speed fan drives added to the Bryan Cave LLP air handling units. 7 Portfolio anager: bus_portfoliomanager 8 DSIR: For more information, visit: eere.energy.gov eere.energy.gov/buildings/commercial/ DO/GO November 2013 Printed with a renewable-source ink on paper containing at least 50% wastepaper, including 10% post consumer waste. Prepared by the National Renewable nergy Laboratory (NRL), a national laboratory of the U.S. Department of nergy, Office of nergy fficiency and Renewable nergy. NRL is operated by the Alliance for Sustainable nergy, LLC.